The present invention relates in general to explosive devices and in particular to a new and useful detonator which requires the simultaneous application of two voltage signals to detonate. One voltage signal is applied to a detonator bridge wire for igniting a weak explosive charge while the other voltage signal, in the form of a high voltage DC pulse, is applied to a piezoelectric semiconductor buffer in the detonator. The detonator is designed to provide an impulse of sufficient amplitude only if the weak explosive and buffer are activated simultaneously. An impulse from either the weak explosive or the buffer alone is insufficient to ignite a secondary of main explosive charge associated with the detonator. The buffer acts to amplify a shockwave from the weak explosive to produce an amplified shockwave of sufficient strength to ignite the secondary of main explosive charge.
Detonators which can be ignited by applying a voltage to a bridge wire alone can be unsafe because of the simplicity of igniting such detonators. Known detonators include a primary explosive main charge which is used for example to ignite a secondary explosive charge, or for other purposes.
Piezoelectric semiconductor devices are also known which, when receiving an electric impulse, produce a mechanical response. Conversely a mechanical impulse on such devices produces an electrical response. Experiments dealing with infinitesimal amplitude (ultrasonic) effect physics of piezoelectric devices can be found in an article by A. R. Hudson, J. H. McFee, and D. L. White, in Physical Review Letters, 7, page 237 (1961). Theory concerning these effects is discussed in an article by D. L. White in J. Appl. Phys., 33, page 2547 (1962).